1. Field of the Invention
The invention relates to amass spectroscopic method, more particularly to a mass spectroscopic reaction-monitoring method.
2. Description of the Related Art
For a liquid sample undergoing a chemical reaction, composition thereof varies over time. State of the chemical reaction can be monitored by monitoring the presence/absence of substances in the liquid sample and quantity changes of the substances.
Various methods, such as classical analysis, Ultraviolet (UV), Nuclear Magnetic Resonance (NMR), Infrared (IR), and neon spectroscopic analyses, have conventionally been used individually or in combination for monitoring chemical reactions. However, time-consuming steps such as separation and purification are required. In addition, instantaneous monitoring of the chemical reaction cannot be conducted. In other words, relative quantities of various substances in a liquid sample cannot be acquired, and the growth and decline of the quantity of each of the substances over a certain period of time cannot be determined.
Although Electrospray Ionization (ESI) mass spectrometry can be used to monitor chemical reactions by making the liquid sample an electrospray solution, the following shortcomings occur as the composition of the liquid sample may be very complicated:                1. it is difficult to remove the liquid portion of the droplets formed by electrospraying (e.g., if the liquid sample is non-volatile);        2. the chemical reaction under monitor is easily affected by the addition of other solvents into the liquid sample for speeding up the removable of the liquid portion of the droplets, and by the addition of acidic substances into the liquid sample for enhancing ionizing efficiency of analytes in the liquid sample, thereby adversely affecting the credibility of the results obtained; and        3. it is prone to misinterpret the obtained mass spectrum when the liquid sample contains salt.        